Glass bells

Lead chamber pmce.ss for H2SO4 intrrxluced by John Roebuck (Birmingham, UK) this immediately superseded the cumbersome small-scale glass bell-jar process (p. 708). 

Plasma polymerization is usually carried out in a low pressure glow discharge sustained by either a dc or an ac electric field. Examples of the reactors used for this purpose are shown in Fig. 1. The simplest configuration involves a pair of circular parallel plate electrodes mounted inside a glass bell jar. The lower electrode usually serves as the substrate holder and is sometimes heated or cooled. Monomer is introduced through a feed tube and unconsumed monomer and gaseous products are withdrawn through a port in the base plate. 

That the calcination of metals when they are contained in a portion of air confined in a glass bell jar does not take place with quite the same facility as in free air. 

The CaCla tube is attached with a piece of pressure tubing to the snout end of the combustion tube through the tube entering the glass bell. The first soda lime tube is attached to the CaC tube through the small tube entering under the stopper. The second soda lime tube is attached to the exit tube of the first in a similar manner. The absorption train is protected with a small tube containing CaClj and soda lime. 

A pretty lecture experiment consists m admitting oxygen to a large glass bell jar filled with nitric oxide, and containing the bulb of an air thermoseope. As the brown fumes are formed, the thermoscope registers a sharp rise in temperature. 

The chlorination of the chloroformate, obtained by the method given on p. 102, was carried out like that of methyl formate, in lead-lined or enamelled vessels. The lids of these vessels were also enamelled and carried eight Osram lamps protected by glass bells. The chlorine was introduced through eight pipes. 

Connect a glass bell-end attachment to the multiplate-end connection. Pressurize the harvest vessel and, via the glass bell-end, remove a small volume of cell suspension for a viable cell count. An MP unit seeded with a minimum of 70 X 10 cells will yield approximately 0.8-1.6 x 10 human diploid cells. For operations involving viral infection instead of trypsinization, the following steps should be considered. 

The substance is spread out in thin layers on /g JL V a watch-glass and placed under a glass bell-jar, under which is also a small dish containing... 

Thus, although there is no air exchange between the glass bell and the surroundings, the Bell method can be used to provide data to calculate the steady state concentration in a ventilated system. 

The process and shape for the glass bell, and the manner of making and rectifying this spirit from the mineral sulphur, or sulphur vive, as it comes stone-like out of the earth, may be seen in the chemical works of Hartman and Crollius, called "ROYAL CHYMISTfRY," Chara s "Royal Pharmacopaea," Lefehure, Thibault, Lemery, Glaser, Shroder s "Dispensatory," and many others, unto whom I refer you.—W C. B. 

The evaporation may be carried out conveniently at room temperature by passing a stream of dry air or inert gas over the surface of the solution under a glass bell. 

Several DTA instruments have been described by Barrall et al. (94, 95). A DTA calorimeter cell in which the AT-sensing thermocouples are attached to the sample container is shown in Figure 6.35. In this apparatus, copper-constantan thermocouples are soldered to a 4-mm-OD copper cup fitted with a copper lid. The thermocouples and sample cups are supported on ceramic insulator tubes which are attached to a metal base. All the cups were heated by thermal radiation received from the blackened copper radiation shield this prevented radiation hot spots due to furnace windings. The entire DTA cell was enclosed by a glass bell jar which provided a controlled atmosphere from reduced pressures to about 2 atm. 

Because of their low vapor pressure, Mo, W and Ta are well suited for building small high-vacuum furnaces. These furnaces are frequently operated under a glass belL The available heating... 

McLeod gauge 2—brass base 3—tungsten plate 4—tungsten tube 5—glass bell ... 

Higher temperatures (up to 3000 C) are reached with tubular timgsten furnaces. Because timgsten is sensitive to Og, and because of the improved thermal insulation, these furnaces must be operated in a vacuum or at least in an Hg or an inert gas atmosphere. A model with horizontal W tube is shown in Fig. 12. The timgsten tube, fixed in place with two sturdy, molybdenum-lined clamps, is supported by two heavy brass bus bars. The latter pass through a thick brass base plate, covered by a large glass bell. 

This observation led us to examine whether Arabidopsis flowers emit terpene volatiles. However, standard volatile collection and analysis techniques did not result in readily detectable levels of terpenes. We, therefore, adapted a closed loop stripping method developed initially by Donath and Boland for the detection of Arabidopsis volatiles. This method (Fig. 1.3A) is based on a continuous circulation of air in the headspace of whole plants or plant parts placed in a 1-3 liter glass bell... 

This device is composed of a glass bell jar, in which a primary vacuum can be achieved using a paddle pump and, if necessary, a diffusion pump. 

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